Power of concentration of a person at a study time usually declines with the passage of time. Accordingly, in many cases, drowsiness comes over the person. To remove the drowsiness, it has been general to take a cup of coffee or take light exercise.
As a method of preventing a fall of wakefulness because of a long-time simple work, there has been studied a method of awakening a person without generating a feeling of discomfort and capable of maintaining wakeful state even when the person is in a long-time monotonous work by controlling a physical stimulus.
As methods of preventing a reduction of wakefulness by controlling a physical stimulus, there are a method of removing a stimulus that makes a person drowsy and a method of actively providing a stimulus that makes a person less drowsy. As the method of actively imparting a stimulus that makes a person less drowsy as the latter method, there has also been progressed a study on the influence of a local exercise stimulus that vibrates a part of a human body, applied to the wakefulness of the person who is in a long-time monotonous work (Non-patent Document 1).
The above study gives a result that the effect of sustaining wakefulness becomes higher when a cycle of the local exercise stimulus that vibrates a part of a human body is shorter (Non-patent Document 1).
Further, it is conventionally known that working five senses at a study time is good to form a brain circuit and establish memory. The “five senses” are five kinds of senses according to a conventional classification, that is, a sense of sight, a sense of hearing, a sense of touch, a sense of taste, and a sense of smell, among many kinds of sensory functions for an animal and a human being to sense an external world. Based on the assumption of this classification, the expression of “five senses” is often used to indicate all senses of a person. In the present specification, the brain circuit refers to a pattern in which information is processed, and much information after being processed is stored in the brain in the form of memory.
On the other hand, the underlay is a collective term of an item that is located beneath an object. The term of underlay is also used to indicate a state of being crushed or overlaid by something such as “trapped under a fallen tree”. However, the underlay, particularly as a common noun, refers to an item that is placed beneath a sheet of paper or the like at a writing time. A material of the underlay that is used for writing with a hard pen such as a pencil and a mechanical pencil is a hard plastic, and is a soft rug (a thick felt that is used as a carpet and the like) for writing with a soft writing brush.
Usually, when a person tries to write letters on a notebook without using an underlay, the paper of the notebook partially sinks and a mark of a writing material may remain on the back of the paper due to a writing pressure of the writer. At the time of writing letters and the like on a sheet of paper, presence of protrusions and indentations beneath the paper or presence of a soft plane beneath the paper makes it difficult to perform the writing. In this case, a hard and smooth sheet is placed beneath the paper to facilitate the writing and set a state of minimizing the mark of the writing material.
A general material is hard polyvinylchloride or a hard paper. In recent years, based on rising concern over environmental issues, underlays that use polypropylene (PP) and polyethylene terephthalate (PET) are becoming general.